I work in the Loop in Chicago, and was looking out the window directly in front of my desk (window faces southeast), and I think I saw a UFO. It was above the 18-story building that fills 2/3rds of the view of my window. It was traveling to my right from the time I first saw it and going in the direction of near south Chicago. It was oval-shaped, 1/4" to 1/2" at arms-length, had no visible wings, moved as though it were floating on top of water, in a horizontal direction (i.e., did not ascend like a balloon would), and had a yellow hue. It was moving away from me, so it was getting smaller, and then I lost it behind a building and in the gray clouds. I called the lady who sits next to me to watch it, and she agreed that it was unidentifiable. We watched it for about 30 seconds before we lost it behind the building.